Field
This disclosure relates generally to fault analysis of data from wafer level testing, and more specifically, to kernel based cluster fault analysis for detecting clustered latent defects caused by systemic process abnormalities.
Related Art
Semiconductor die are tested for failures at various stages through device production, such as at wafer level testing after the semiconductor wafer is fabricated, and again at burn-in stress testing after the semiconductor die are assembled into packages. Any failed die detected during such testing are discarded. If the failed die is assembled into a package, the entire package is discarded. It is beneficial to identify failed die as early as possible in the device production flow in order to reduce device production costs. However, while burn-in stress testing attempts to identify parts that are likely-to-fail in their life cycle, burn-in stress testing can cause overstressing of parts and may result in degrading the packages and overall product quality. Burn-in stress testing can also be an expensive step in a device test flow due to expensive equipment and long stress duration. For these cost and quality concerns, it is desirable to minimize the use of burn-in stress testing in a device test flow.
The present invention is illustrated by way of example and is not limited by the accompanying figures, in which like references indicate similar elements, unless otherwise noted. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.